docs: def get_distance_term(self, C, rup, rjb, imt):
          """
          Returns the distance attenuation factor
          """
          h = self._get_h(C, rup.hypo_depth)
          rval = np.sqrt(rjb ** 2. + h ** 2.)
          c3 = self.get_distance_coefficients(C, imt)
  
          f_r = (C["c1"] + C["c2"] * (rup.mag - self.CONSTANTS["Mref"])) *\
              np.log(rval / self.CONSTANTS["Rref"]) +\
              c3 * (rval - self.CONSTANTS["Rref"])
          return f_r